In a large skillet, cook Italian sausage and diced onion until sausage is done. Drain well and allow to cool.

Preheat oven to 350 degrees F. Oil the insides of a muffin tin and set aside.

In a medium bowl, blend pizza mix, salt, parmesan, butter, water and eggs. Then stir in cheese and cooked sausage. Using an ice-cream scoop (1/4 cup measurement), scoop pizza batter into prepared pan. Top with extra cheese and pepperoni slice.

Bake for 20 minutes. Allow to cool 5-10 minutes (to allow cheese to harden a bit) before removing from pan.